The present invention generally relates to the area of methods and systems for maintaining and using information relating to the contents of a file (i.e., metadata). More particularly, the present invention relates to multimedia file metadata storage and retrieval schemes.
Multimedia file metadata consists of information relating to, and often describing the content portion of a multimedia file. Metadata is typically not the data of primary interest to a viewer of the file data contents. Instead, file metadata information comprises supporting information providing a context to the situation in which the image/voice content data was recorded or modified. Examples of multimedia file metadata include: time, date, author, subject, comments (including audio attachments), frame width, frame height, etc.
Multimedia metadata information is generally created or updated when a multimedia file is created or edited, and a number of different sources provide such metadata. An author or editor designates metadata for a multimedia file. The user may designate the metadata at the time of initial recording via a user input interface on a recording device. Alternatively, a user provides metadata at a later time by means of a multimedia file editor application program. In other instances, a device that creates/modifies the multimedia file automatically renders file metadata according to device settings or sensed conditions.
The popularity of digitally recording audio/visual works has rapidly increased over the past decade. Higher capacity memory devices, improved integrated circuit technology, and improved data compression/encoding formats have contributed to making digital storage of audio/visual works both desirable and commercially feasible.
Multimedia file metadata is becoming more important as users increase their reliance upon digital storage media to store vast amounts of photographs and audio/visual recordings rendered by digital cameras and other digital multimedia recording equipment. The archived digital multimedia files may number in the hundreds or even thousands on a single computer or directory. The presence of metadata, such as an xe2x80x9ceventxe2x80x9d field, in such files provides a useful means for searching and arranging the stored metadata files in a meaningful manner.
While older model cameras and video cameras stored time and date metadata information types, new digital multimedia equipment and software support dozens of metadata types for storing metadata recorded and output to users in a variety of formats (including both audio and visual output interfaces). Furthermore, software developers have created a number of sophisticated applications for recording, editing and maintaining the multimedia recordings and their associated metadata. The enhanced body of metadata supported by today""s metadata schemes facilitates a variety of unique and meaningful file search and arrangement strategies/functions.
The rapid development of digital imaging technology has primarily occurred through independent efforts of particular associations. As a result of independent development efforts, there is presently no universal metadata standard for digital images. Instead several differing metadata specifications have been promulgated in association with each of the differing digital image encoding formats. Examples of the various digital image encoding formats include: TIFF, EXIF, BMP, PNG, and GIF. Each digital image encoding format has its own distinct specification for representing metadata associated with a digital image file (i.e., metadata scheme).
Today""s multimedia applications support/utilize a variety of metadata storage schemes. Each metadata scheme defines supported metadata types and a manner for storing metadata of the supported metadata types. Many, if not most, of the present multimedia applications support only a single or limited number of metadata storage schemes. The combination of multiple multimedia metadata schemes and limited decoding capabilities within applications substantially limit the potential utility of multimedia applications with regard to retrieving and presenting metadata for multiple file types to users and directory arrangement/presentation tools.
Efforts have been made to accommodate the existence of multiple differing digital image metadata formats. Currently, one solution to the proliferation of multiple differing image metadata formats is to include a metadata decoder within image processing applications for each supported image format. In addition to the above proposed solution, there has been an effort to specify a universal, XML-based image metadata scheme. Image file metadata decoders within applications created in accordance with the proposed universal metadata scheme utilize the extensible universal image metadata specification to decode image metadata stored according to the universal specification. The extensible quality of the universal standard facilitates updating the universal specification to include new metadata types. The universal metadata scheme does not contemplate backward compatibility. Thus, universal scheme metadata decoders will not support any of the above-mentioned predecessor metadata formats. If the universal specification is successful, the number of applications supporting the xe2x80x9coldxe2x80x9d formats will likely dwindle thus leaving the owners of digital images encoded in the old formats with a diminishing supply of applications supporting their images"" formats.
The present invention comprises an infrastructure and method for providing format-independent access by applications to multimedia file metadata originally provided in any of a set of supported formats. More particularly, in accordance with the present invention, a metadata abstraction interface is interposed between multimedia files and applications that seek to read metadata associated with the multimedia files.
The metadata abstraction interface supports program access to multimedia file metadata provided in a variety of formats and comprises a multimedia application program interface corresponding to a set of core multimedia file metadata management functions accessible by multimedia applications. Programs (e.g., applications), through the application program interface, submit requests to read and/or modify metadata contents of multimedia files. The requesters need not know or specify the format of the multimedia files and their corresponding metadata.
The metadata abstraction interface includes an extensible set of metadata decoders. Each decoder includes a metadata converter for parsing a metadata portion of a multimedia file stored in a particular native format (e.g., .bmp). The decoders render metadata in a generic format from the parsed metadata. The generic format insulates the applications from the differences present in the various multimedia file metadata formats.
The multimedia application program interface comprises a set of program instruction segments within the metadata abstraction interface for invoking particular ones of the extensible set of metadata decoders to obtain and/or modify metadata corresponding to a multimedia file. Thus, applications need only follow a simple set of interface rules when requesting a metadata related request. The requests need not consider the manner in which a particular set of file metadata is stored since the decoders and encoders of the abstraction interface handle differences between various native multimedia file formats.